Method of making foundry moulds

ABSTRACT

A method is provided for making foundry moulds which comprises pressing moulding sand in a flask between a thrust plate and a pattern plate with patterns therein, and pressing the moulding sand also by a stripper plate. The pattern plate and stripper plate are moved independently of each other along a portion of a complete pressing stroke and at the end of the pressing stroke both plates are moved simultaneously to complete the motion. Thereupon the patterns are slightly withdrawn from the thusly compacted mould by the stripper plate whereafter all of the components are returned to the initial position.

United States Patent l Inventors Benedikt Veniaminovich Rabinovi ch Yauzsky bulvar l4, kv. l6; and Fedor Filippovich Rezinskikh, Kerchigskaya ul., 26, k'v. 9, both of Moscow, U.S.S.R. Appl. No. 4,730 Filed Aug. 31, 1967 Patented Jan. 5, 1971 METHOD OF MAKING FOUNDRY MOULDS 5 Claims, 7 Drawing Figs.

us. (I 164/44, 164/188 Int. Cl. B22c 15/08 Field ofSearch... 164/37, 15,

[5 6] References Cited UNITED STATES PATENTS 1,006,449 10/ l 91 1 Duncan 1,966,941 7/1934 Yager et a1.

Primary Examiner-J. Spencer Overholser Assistant Examiner--John S. Brown Attorney-Waters, Roditi, Schwartz & Nissen ABSTRACT: A method is provided for making foundry moulds which comprises pressing moulding sand in a flask between a thrust plate and a pattern plate with patterns therein, and pressing the moulding sand also by a stripper plate. The pattern plate and stripper plate are moved independently of each other along a portion of a complete pressing stroke and at the end of the pressing stroke both plates are moved simultaneously to complete the motion. Thereupon the patterns are slightly withdrawn from the thusly compacted mould by the stripper plate whereafter all of the components are returned to the initial position.

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' "PATENTED JAN slsrl SHEET 2 BF 3 PATENTEU JAN 5197:

Y SHEET 3 BF 3 m Qt , but the moulding sand is likely to lose its flowability as it said disadvantages.

This invention relates to a'new method of making foundry FIG. 3 is a sectional view of the device for making foundry moulds when utilizing the upper sand frame, shown in the inimoulds, and more particularly to methods ofinaking foundry moulds by pressing and to devices for effecting same.

Known in the-prior art is a method of making foundry moulds by pressing moulding sand in a flask between a shaped thrust plate and a pattern plate.'ln conformity with this method, the pattern plate together with patterns secured thereon is placed inside the frame of 'a; moulding machine below theflask joint, said flask being put on the frame, and the entire space is filled with moulding sand, while the flask with the moulding sand is forced from the side opposite to the mould joint toward the shaped thrustplate, leaving thereby its cavities free from the moulding sand; the flask and shaped thrust plate are then fixed in this positionQthe pattern plate is thereafter lifted, thus pressing the moulding sand. The degree of compaction of the moulding sand, disposed above the portions of patterns of different heights, is adjusted by varying the v depth of the' cavitiesin the shaped thrust plate or by providing projections thereon In those cases; however, where narrow spaces were present between the'adjacentpatterns, while the patterns had cavities,

the moulding sand was not pressed in these places, and the resulting foundry mould was thus of a poor quality. Friction of the moulding .sand against .the pattern walls during the pressing operation. interfered with the compaction in these Zones v I To eliminate this disadvantage, the space betweenpatterns has been widened, which resultedin decreasing the number of patterns that could be mounted on the pattern plate, thus reducing the productivity. Vibration has been also resorted to,

IS. compacted, which diminishedthe vibrational effect.

An object of the present invention A further object of the invention is toprovide a method of making foundry moulds by pressing in which the friction of the moulding mixture against the pattern'walls does not interfere v with the compaction. of a mould; rather it contributes to the compression thereof, which results in the provision of the required compaction of the-moulding sand in narrow spaces "between patterns and in cavities of the pattern itself.

' the pressing stroke independently from one another; at the end of the operation of pressing they are brought together in such a manner as to prevent any displacement between them toeliminatethe abovetial position;

' FIG. 4 is a sectional view of the device, as is illustrated in FIG. 3,'shown on completing the pressing operation;

FIG. 5 is an enlarged sectional view of the device complete with an-arrangement for compacting the projecting portions of a mould or cods, shown in the initial position;

FIG. 6 is an enlarged sectional view of the device complete with an arrangement, similar to that shown in FIG. 5, with the layout of parts ensuring the formation of an additional layer of the moulding sand for the subsequent pressing of the cod; and

FIG. 7 is an enlarged sectional view of the device complete with an arrangement similar to that illustrated in FIGS. 5 and 6, but shown on completing the operation of pressing.

The device (FIGS. 1 to 7) comprises a stripper plate I; a piston 2; a pattern plate 3; patterns 4; a piston 5; power cylinders 6, whose rods are provided with stops adjustable in the vertical direction; a frame 7 of the moulding machine; a flask 8; a shaped thrust plate 9; a crosspiece 10 of the moulding machine; vertically adjustable stops '11; a cylinder 12; an upper sand frame 13; a movable insertion piece 14-, a spring 15, and a vertically adjustable stop 16.

All the above-mentioned parts are clearly shown in the accompanying drawings. The parts 2, 5 and 12, are shown in the drawings but partially (FIGS. 1 to 4), as representing the existing devices, in which the part 2 functions as a piston in relation to the cylinder 12, and is simultaneously employed as a cylinder for the piston 5. In all other embodiments, the pistons 2 and 5 may be disposed independently from each other.

EXAMPLE I Atthe beginning of the manufacturing process, the com stripper plate 1 is secured on the piston 2, while the pattern plate 3 with patterns 4, on the piston 5. Simultaneously, the pattern plate 3 is resting on rods of the cylinders 6. In the initial position of the device thus shown, as well as during the process of pressing the moulding sand, each rod is lifted until it thrusts against the cylinder cover. All the moulding assembly is lowered in the frame 7 of the moulding machine by a value of the pressing stroke equal to A In this position, the flask 8 is put on the frame 7, and the'space thus formed is filled with the moulding sand. The. flask together with the and to complete the motion simultaneously. Then the pattern is somewhat withdrawn from the compacted mouldjthrough their initial position.

To carry' the methodof the invention into effect a device hasbeen designed, having the frame of a moulding machine with a movable pattern plate with patterns arranged inside thereof, in which, according to the invention, a movable stripper plate is provided betweenthe moulding machine frame and pattern plate, coupled witha pressing piston and supporting power cylinders, whose rods support the pattern plate coupled with another pressing cylinder.

Other objects and advantages of the invention will become more fully apparent from the following description of exemplary embodiments of the invention, schematically represented in the accompanying drawings, in which:

FIG. I is a sectional view of the device in its initial position for making foundry moulds when utilizing'the bottom sand frame; 7

FIG. 2 is a sectional view of the same device, illustrated in FIG. 1, shown on completing the pressing operation;

moulding sand is brought into contact with the shaped thrust plate 9, attached to the crosspiece 10 of the moulding machine, and is fixed in this position. Depending upon the shape of patterns and degree of compaction of the mould desired, the shaped thrust late 9 is provided with cavities varying in height.

The pressing of the moulding sand is started by the motion of the piston 5, which is employed for moving the pattern plate 3 with the patterns 4 through a distance A (not shown in the drawings), smaller than the complete stroke A, by a certain value B (not shown on the drawings), whereupon the piston together with the pattern plate and patterns is stopped.

Then the piston 2 with the stripper plate 1 is started to be moved. Their complete stroke is equal to A,,. In the process of raising, the stripper plate 1 reaches the pattern plate 1, upon which, on its way, the stripper plate 3 with the help of rods of the cylinder 6, engages the pattern plate 3 (together with the piston 5) and moves them together through a distance 8 until stops 11 thrust against the'fl'ame 7 of the moulding machine. Owing to this, on completing the pressing stroke A,,, the entire moulding assembly is stopped precisely in the plane of the frame 7 and in the joint of the flask 8 (FIGS. 2).

On relieving the pressing force, the rods of the cylinders 6 are lowered, and under the action of the piston 5 the patterns 4 are somewhat withdrawn through the stationary stripper plate 1, which is thereby supporting the mould. Then the piston 2 together with the stripper plate is lowered, as a result of which the pistons and the entire" moulding assembly are returned to the initial position. Furthermore, as usual, the crosspiece 10 together with the shaped thrust plate 9 are lifted and brought aside, and the mould is'removed from the frame 7.

The symbols employed in the description thus presented may assume the following values: H,,=250 mm., h=l80 mm., A,,=l75 mm., A=l mm., B=75 mm.

EXAMPLE 2 The initial and final position of components of the device are the same as those shown in the first example (FIGS. 1 and 2). The second example differs in that the pattern plate and stripper plate are simultaneously started to be moved, but the former is moved at a faster speed than the latter. After the pattern plate has been moved through a distance A, it is stopped; then it is engaged by the stripper plate, further the moulding process goes on as set forth in the first example.

The method represented by the second example, allows a reduction in the compacting time and an increase in the productivity as compared with the method of the first example. On account of a shorter path of the motion of the stripper plate with respect to the patterns, the moulding sand found in the narrow spaces between the patterns will be compacted to a smaller degree. For this reason, the working routine, as described in the second example, is recommended with a comparatively free disposition of the patterns.

EXAMPLE 3 In those cases when the pattern is of a constant height h," the shaped thrust plate 9 may be replaced by a flat thrust plate. Let us suppose that under these conditions for compacting the layer of the moulding sand above the pattern, it must have a stroke A (not shown in the drawings). In the initial position, the stripper plate is lowered below the frame plane by a value A,,, as in the first example (FIG. 1), whereas the joint of the patterns is raised above the stripper plate by a value (A -A The compression of the moulding sand is started by the mutual motion of the stripper plate and pattern plate. They move together through a distance shorter than the stroke A by a certain value B, whereupon the pattern plate is stopped, while the stripper plate is continued to be moved. As soon as the stripper plate is moved through a distance (A -A), its plane will coincide with the joint of the patterns. With the further motion of the stripper plate, it engages the pattern plate, and they are moved together through the last portion of the stroke B. The pressing operation is completed by this motion (FIG. 2).

Thereupon, the moulding operations are carried out as set forth in the first example.

The symbols employed in the description thus stated may assume the following values: I-I,,=25O mm., h=l80 mm., A,,=l75 mm., A =50 mm., A,,-A mm., B=l0 mm., A=b 40 mm.

EXAMPLE 4 If narrow spaces were not formed between the patterns and flask walls, and they are present only between the patterns, the frame of the moulding machine becomes unnecessary and the design of the stripper plate may be simplified, which reduces the cost of the whole device and facilitates making moulds of various size in the same moulding machine.

At the beginning of the process, the components of the device are disposed so as is shown in FIG. 3. The stripper plate 1 is secured on the piston 2, while the pattern plate 3 with the patterns 4 on the piston 5. Simultaneously the pattern plate 3 rests upon the rods of the cylinders 6. In this initial position of the device and in the process of compression of the moulding sand, each rod is elevated until it thrusts against the cylinder cover. A flask 8 with a sand frame 13 having a height H equal to A (i.e.. to the full stroke of the pistons 2 and 5, as well as to that of the pattern plate 3 and stripper plate 1), are put on the stripper plate 1 and filled with the moulding sand. The shaped thrust plate 9, secured on the crosspiece 10 of the moulding machine, is placed above the flask with the sand frame and pressed against the surface of the moulding sand. Depending upon the shape of the patterns and the desired degree of compaction of the mould, the shaped thrust plate 9 has cavities varying in height.

The pressing of the moulding sand is started by the motion of the piston 5, by means of which the pattern plate 3 with the patterns 4 is displaced through a distance A (not shown in the drawings smaller than the complete stroke A,, by a certain value B (not shown in the drawings), whereupon the piston together with the pattern plate and patterns are brought to a halt.

Then the piston 2 with the stripper plate I and the flask 8 placed thereon are moved, as a result of which the shaped thrust plate 9 enters the sand frame l3. The complete stroke of the piston 2 with the stripper plate I amounts to as much as A In the process of raising of the stripper plate, it reaches the pattern plate 3, whereupon, on its way, the stripper plate I by means of rods of the cylinders 6 engages the pattern plate 3 and moves them together through a distance B until the sand frame 13 thrusts against the crosspiece 10. On completing the operation of compacting, the shape and positioning of the components of the device are shown in FIG. 4.

On relieving the pressing force, the rods of the cylinders 6 are lowered, and under the action of the piston 5, the patterns 4 are withdrawn to some degree through the stationary stripper plate 1, which is thereby supporting the mould. The crosspiece 10 with the shaped thrust plate 9 are as usually lifted and brought aside, while the frame 13 and flask 8 are removed. Then the pistons 2 and 5 are lowered, and the whole moulding assembly is brought to its initial position.

The symbols employed in the description thus stated may assume the following values: H =250 mm., li=l mm., I-I=A,,=mm., A=l00 mm., B=75 mm.

The arrangement thus described may be employed also for making moulds in accordance with practices stated in the second and third exemplary embodiments.

EXAMPLE 5 When the mould features projecting portions or cods, i.e., rather high compared with their width, disposed inside the pattern, their pressing is effected by means of a stripper plate when using an additional arrangement (FIGS. 5 to 7). It may also be employed in all the four examples stated above. In this example, the operation of the device is considered when using the moulding outfit and according to the moulding process as shown in FIGS. 1 and 2. In the initial position of the moulding assembly, a movable insertion piece I4, forming the end face of the cod, is pressed by a spring 15 against a vertically adjustable stop 16, which is screwed into the bracket of the stripper plate 1 (FIG. 5). The subsequent displacement of the insertion piece in relation to the pattern is determined by a size A which may be smaller or greater than the height of the cod. When the piston 5 with the pattern plate 3 and patterns 4 are moving (see the first example and FIGS. I and 2), the insertion piece 14 remains stationary (pressed against the stop 16) until the pattern 4 covers the distance A Thereafter, an additional layer of the moulding sand is formed in the pattern 4 below the cavity forming the cod, the thickness of this layer being equal to A With the further motion of the pattern plate, the insertion piece 14 is moved together with the pattern 4, and is brought aside from the stop 16. After the pattern plate has been stopped, in the process of the subsequent motion of the stripper plate I, the insertion piece 14 is engaged by its stop 16 and is displaced by the value ol'the strike A followed by the compaction of the cod. On completing the pressing of the cod and the entire mould, the positioning of the components of the device is shown in FIG. 7. When the pattern 4 is withdrawn from the compacted mould, the insertion piece I4 together with the stripper plate are left stationary in order to support the cod.

EXAMPLE 6 In contradistinction to the fifth exemplary embodiment, in the initial position the pattern 4 islifted above the plane of the stripper plate 1 by a value A, (FIG. 6), owing to which an additional layer of the moulding sand (for the subsequent compaction of the cod) is formed at the stage of filling the flask with the moulding sand. Such a technique is likely to improve the conditions of filling the pattern cavity by the moulding sand. Simultaneously, there are impaired the conditions under which are filled with the moulding sand the spaces between the patterns and flask walls as well as spaces between the patterns on account of an increase in the height of the spaces due to the lifting of the patterns over the stripper plate. For this reason, the technique described herein is recommended for cases where the cavity in the pattern is comparatively narrow, while the spaces between the patterns and flask walls, as well as between the patterns proper are sufficiently large.

The sequence of operations in moving-the components of the device, and all the operations of the process of making the mould in this case are effected in; the same manner as described above.

We claim:

l. A method of making foundry moulds comprising pressing molding sand in' a'flaskbetweena thrust plate'and a pattern plate with patterns therein; pressing said molding sand also by a stripper plate, saidpattern plate and stripper plate being moved independently of each otheralong a portion of a complete pressing stroke, and, at the end of the pressing stroke, moving both plates in such a manner that they db not move relative to each other an complete the motion simultaneously; and thereupon withdrawing the patterns slightly from the thusly compacted mold through said stripper plate, which supports the moulding sand, whereupon all the components of the device are brought back to initial position, said thrust plate being shaped, the motionof said pattern plate and stripper plate being started simultaneously; said pattern plate being initially moved at a greater speed than said stripper plate and after moving them in such manner along a portion of the complete pressing stroke said pattern plate is stopped, and said stripper plate is continued to be moved in the same direction until said stripper plate engages said pattern plate for effecting their common motion in the last stage of the pressing operation. 1

2. A method of making foundry molds comprising pressing molding sand in a flask between a thrust plate and a pattern plate with patterns therein; pressing said molding sand also by from the thusly compacted mold through said stripper plate, which supports the molding sand, whereupon all the components of the device are brought back to initial position, said thrust plate being flat, said pattern plate and patterns being lifted into an initial position above the. plane of said stripper plate, the pattern plate together with said stripper plate being first moved along a greater portion of the complete pressing stroke required for compacting the molding sand layer above the patterns; said pattern plate then being stopped while said stripper plate continues to move in the same direction such that said stripper plate engages said pattern plate for effecting their common motion in the last stage of the pressing operation.

3. A method of making foundry molds comprising pressing molding sand in a flask between a thrust plate and a pattern plate with patterns therein; pressing said molding sand also by a stripper plate, said pattern plate and stripper plate being moved independently of each other along a portion of a complete pressing stroke, and, at the 'end of the pressing stroke, moving both plates in such a manner that they do not move relative to each other and complete the motion simultaneously; and thereupon withdrawing the pattern sllghtly from the thusly compacted mold through said stripper plate,

which supports the molding sand, whereupon all the components of the device are brought back to initial position, said mold having cods disposed inside of the patterns and for their compacting by said stripper plate an insertion piece is displaceably inserted in the patterns to form end faces for the cods, moving said insertion piece and'patterns relative to one another during one of the molding stages such that the cavity in the mold is deepened as compared with the height of said cod in the finished mold; filling the cavity thus obtained with molding sand, whereupon, the stripper plate, during the independent motion thereof, moves said insertion piece in relation to the associated pattern, and the respective cod is compacted until its final dimension is obtained; whereafter during the subof the cavity, forming the cod, and filling of the cavity thus oba stripper plate, said pattern plate-and stripper plate being tained by the molding sand in the course of the pattern motion, and along a portion of the stroke whereof said insertion piece is left stationary.

5. A method according to claim 3 comprising effecting the relative displacement of said insertion piece and pattern, deepening of the cavity, and forming the cod in the initial position due to the lifting of the pattern over the plane of said stripper plate, while the cavity thus obtained is filled with the molding sand simultaneously with its being supplied into the flask. 

1. A method of making foundry moulds comprising pressing molding sand in a flask between a thrust plate and a pattern plate with patterns therein; pressing said molding sand also by a stripper plate, said pattern plate and stripper plate being moved independently of each other along a portion of a complete pressing stroke, and, at the end of the pressing stroke, moving both plates in such a manner that they do not move relative to each other an complete the motion simultaneously; and thereupon withdrawing the patterns slightly from the thusly compacted mold through said stripper plate, which supports the moulding sand, whereupon all the components of the device are brought back to initial position, said thrust plate being shaped, the motion of said pattern plate and stripper plate being started simultaneously; said pattern plate being initially moved at a greater speed than said stripper plate and after moving them in such manner along a portion of the complete pressing stroke said pattern plate is stoppeD, and said stripper plate is continued to be moved in the same direction until said stripper plate engages said pattern plate for effecting their common motion in the last stage of the pressing operation.
 2. A method of making foundry molds comprising pressing molding sand in a flask between a thrust plate and a pattern plate with patterns therein; pressing said molding sand also by a stripper plate, said pattern plate and stripper plate being moved independently of each other along a portion of a complete pressing stroke, and, at the end of the pressing stroke, moving both plates in such a manner that they do not move relative to each other and complete the motion simultaneously; and thereupon withdrawing the patterns slightly from the thusly compacted mold through said stripper plate, which supports the molding sand, whereupon all the components of the device are brought back to initial position, said thrust plate being flat, said pattern plate and patterns being lifted into an initial position above the plane of said stripper plate, the pattern plate together with said stripper plate being first moved along a greater portion of the complete pressing stroke required for compacting the molding sand layer above the patterns; said pattern plate then being stopped while said stripper plate continues to move in the same direction such that said stripper plate engages said pattern plate for effecting their common motion in the last stage of the pressing operation.
 3. A method of making foundry molds comprising pressing molding sand in a flask between a thrust plate and a pattern plate with patterns therein; pressing said molding sand also by a stripper plate, said pattern plate and stripper plate being moved independently of each other along a portion of a complete pressing stroke, and, at the end of the pressing stroke, moving both plates in such a manner that they do not move relative to each other and complete the motion simultaneously; and thereupon withdrawing the pattern slightly from the thusly compacted mold through said stripper plate, which supports the molding sand, whereupon all the components of the device are brought back to initial position, said mold having cods disposed inside of the patterns and for their compacting by said stripper plate an insertion piece is displaceably inserted in the patterns to form end faces for the cods, moving said insertion piece and patterns relative to one another during one of the molding stages such that the cavity in the mold is deepened as compared with the height of said cod in the finished mold; filling the cavity thus obtained with molding sand, whereupon, the stripper plate, during the independent motion thereof, moves said insertion piece in relation to the associated pattern, and the respective cod is compacted until its final dimension is obtained; whereafter during the subsequent withdrawal of the patterns from the compacted mold, each said insertion piece together with said stripper plate are left stationary thus supporting the respective said cod.
 4. A method according to claim 3 comprising effecting the relative motion of said insertion piece and pattern, deepening of the cavity, forming the cod, and filling of the cavity thus obtained by the molding sand in the course of the pattern motion, and along a portion of the stroke whereof said insertion piece is left stationary.
 5. A method according to claim 3 comprising effecting the relative displacement of said insertion piece and pattern, deepening of the cavity, and forming the cod in the initial position due to the lifting of the pattern over the plane of said stripper plate, while the cavity thus obtained is filled with the molding sand simultaneously with its being supplied into the flask. 